Flexible turbine blade

ABSTRACT

Systems and techniques relating to blades, in particular to symmetrical blades for turbines. In one general implementation, the present application relates to a method for increasing efficiency of a symmetrical blade comprising providing a rigid portion of the symmetrical blade and providing a flexible portion of the symmetrical blade. The rigid portion of the symmetrical blade can be connected to the flexible portion of the symmetrical blade. The flexible portion of the symmetrical blade can be adapted to bend with a flow across the symmetrical blade. The symmetrical blade can be adapted to rotate in one direction for a bi-directional flow across the symmetrical blade. The symmetrical blade can be adapted for at least one of a Wells Energy Conversion (WEC) system, a fan, an exhaust system, a blowing system, and a suction system. The rigid portion of the symmetrical blade can be fixed to an axis perpendicular to a direction of flow. The symmetrical blade can be rotated in a direction orthogonal to the direction of flow and orthogonal to the bending of the symmetrical blade. The rigid portion may comprise metal, wood, and plastic. The flexible portion may comprise plastic and rubber. The symmetrical blade may comprise a pear-shaped blade or a rectangular-shaped blade.

BACKGROUND

Conventional turbines typically have solid, rigid structures to form blades for the turbines. Such rigid blades are able to rotate at high speeds under normal conditions. However, when it is desired that the turbine blade rotates in the same direction regardless of the flow direction, symmetrical blades are often desired. For example, a Wave Energy Conversion (WEC) system can require that the turbine blade rotates in the same direction regardless of the flow direction. Such a system can use a Wells Turbine. However, the Wells Turbine has symmetrical, rigid blades and relatively low efficiency. Wells turbines with variable pitch, rigid blades to improve efficiency are being designed and tested but the variable pitch technology is very different from the flexible turbine blade described in the present application.

SUMMARY

The present application describes systems, methods and techniques for a flexible blade turbine system.

One aspect of the present application relates to a method for increasing efficiency of a symmetrical blade comprising providing a rigid portion of the symmetrical blade and providing a flexible portion of the symmetrical blade. The rigid portion of the symmetrical blade can be connected to the flexible portion of the symmetrical blade. The flexible portion of the symmetrical blade can be adapted to bend with a flow across the symmetrical blade. The symmetrical blade can be adapted to rotate in one direction for a bi-directional flow across the symmetrical blade. The symmetrical blade can be adapted for at least one of a Wave Energy Conversion (WEC) system, a fan, an exhaust system, a blowing system, and a suction system. The rigid portion of the symmetrical blade can be fixed to an axis perpendicular to a direction of flow. The symmetrical blade can be rotated in a direction orthogonal to the direction of flow and orthogonal to the bending of the symmetrical blade. The rigid portion may comprise metal, wood, and plastic, wherein the flexible portion may comprise plastic and rubber. The symmetrical blade may comprise a pear-shaped blade or a rectangular-shaped blade.

In another aspect, the present application may describe a system for increasing the efficiency of a turbine with a symmetrical blade. The system may comprise a rigid portion of the symmetrical blade and a flexible portion of the symmetrical blade. The flexible portion of the symmetrical blade may connect to the rigid portion of the symmetrical blade, wherein the flexible portion is adapted to bend in a direction of flow across the symmetrical blade. The geometry of the symmetrical blade can vary to reduce an amount of loss from an entirely rigid, symmetrical blade. The geometry of the symmetrical blade can also vary to increase the efficiency of the symmetrical blade over an entirely rigid symmetrical blade. The symmetrical blade can be adapted to rotate in a single direction for a bi-directional flow across the symmetrical blade. The symmetrical blade may comprise plastic and metal.

Details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages may be apparent from the description, drawings, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects will now be described in detail with reference to the following drawings.

FIG. 1 illustrates a top view of an exemplary blade.

FIG. 2 illustrates a side view of an exemplary blade.

FIG. 3 illustrates a top view of a flat exemplary blade.

FIG. 4 illustrates a top view of an exemplary blade comprising one flexible portion between two rigid portions.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

The systems and techniques described here relate to a blade for turbine or fan systems. In particular, the system described herein relates to a blade that rotates in the same direction regardless of a flow direction (e.g., bi-directional flow). The disclosed system may provide higher efficiencies than conventional symmetric blades responding to bi-directional flows.

A symmetrical blade can allow the blade to rotate in one direction regardless of the direction of a flow across the blade. Such a flow may be referred to as a bi-directional flow. In conventional systems, such as a Wave Energy Conversion (WEC) system, the symmetry of the blade can lead to lower efficiencies than a conventional non-symmetrical turbine blade. A typical turbine that can be used for a WEC system may be a Wells Turbine. A Wells Turbine has rigid, symmetrical blades. The system described herein can provide a higher efficiency than the efficiency of a Wells Turbine.

FIG. 1 shows an exemplary schematic diagram of a top view 130 of a blade 105. FIG. 2 shows an exemplary schematic diagram of a side view 210 of the blade 105. The blade 105 may be a symmetrical blade 105. When looking at the top view 130 of the blade 105, the blade may have a total length M 104. The blade 105 can have a firmly mounted portion 135 of length L 125 on the X axis 110. The blade 105 can have a portion 140 of length N 102 that is not firmly mounted on the X axis 110. The total blade length M 104 is the sum of lengths L 125 and N 102. The blade 105 can wobble around the Z axis 220 and have the freedom to also move in the X-Y plane 110, 120. The flow direction in this exemplary embodiment is shown in the y direction 120. The flow direction may be in a positive y direction, a negative y direction, or the positive y direction for one time period and the negative y direction in another time period. The blade 105 may be (1) partially rigid and partially flexible, (2) entirely rigid, or (3) entirely flexible.

In one aspect, the blade 105 may be partially rigid and partially flexible. The blade 105 can have firmly mounted part 135 of length L 125 on the X axis. The blade 105 may also have a length N 102 on the X axis towards the trailing edge 140 (e.g., tail part) that allows a flapping movement 115. The bending/flapping movement 115 can be in response to a force and a direction of flow. The flexible portion 140 of the blade 105 can bend with the flow direction and give the turbine blade more impulse. The bending of the blade 115 allows the blade 105 to rotate faster than a conventional, rigid Wells turbine blade. The bending of the blade 115 can allow the geometry of the symmetrical blade 105 to vary from a conventional rigid, symmetrical blade. The varying geometry of the symmetrical blade 105 can reduce an amount of loss and increase the efficiency of the symmetrical blade 105 over a conventional rigid, symmetrical blade.

In another aspect, the blade 105 can be entirely rigid. For this aspect, length L 125 is equal to length M 104 and length N 102 is zero. The rigid blade 105 may rotate in a direction of the Z axis 220 without the bending of the blade 115.

In another aspect, the blade 105 can be entirely flexible. For this aspect, length L 125 is zero and length N 102 is equal to length M 104. The blade 105 can bend in response to the flow direction. The entire blade 105 can also rotate around the Z axis 220. In one embodiment, the blade 105 may bend in a y direction 120 and not rotate around the Z axis 220. In another embodiment, the blade may not bend in a Y direction 120 and rotate around the Z axis 220. Under typical operation, the blade 105 can both bend 115 in the y direction 120 and rotate around the Z axis 220. The amount of bending 115 may depend on an intensity of the flow, the flexibility of the blade 105, and the amount of rotation around the Z axis 220.

The entirely flexible blade 105 can bend with the flow direction and give a turbine blade more impulse. The entirely flexible blade 105 has the freedom to move in the X direction and/or the y direction. The entirely flexible blade 105 may rotate faster than a rigid Wells Turbine blade. The flexibility of the symmetrical blade 105 may (1) vary the geometry of the blade 105, (2) reduce the losses of the blade 105 and (3) increase the efficiency of the blade 105 over a rigid, symmetrical blade.

The blade 105 may be constructed out of a material that can allow the blade 105 to have a flexible portion and/or a rigid portion. For example, the blade 105 may have a rigid portion made from materials such as hard plastic, wood, or metal. The blade 105 may have a flexible portion made out of materials such as plastic or rubber. The blade 105 may be constructed with a hard plastic material for a rigid portion 135 and a flexible plastic material for the flexible portion 140. The rigid portion 135 and flexible portion 140 may be one piece of material or two or more attached pieces of material.

The blade 105 may operate in other systems other than WEC systems. For example, the blade 105 may operate in suction systems and blowing systems. The blade 105 may also operate in exhaust systems and fans.

In another aspect, the blade 105 may be have a different shape other than what is shown in FIGS. 1-2. For example, the blade 105 may have a rectangular or flat shape as shown in FIG. 3.

In another aspect, the blade 105 may have a flexible portion 137 of length N 102 positioned between a rigid portion 135 of length L 125 fixed to the X axis 110 and a rigid portion 440 of length p 128 that is not fixed to the X axis 110 as shown in FIG. 4. The bending of the blade 105 at 115 may occur along the flexible portion 137 that is positioned between the two rigid portions 135,440. The blade 105 may also rotate around the Z axis 220.

In another aspect, the rigid portion 135 (FIG. 4) may have a length L 125 of zero. The total length M 104 of the blade 105 may comprise the flexible portion 137 of length N 102 and a rigid portion 440 of length p 128. The flexible portion 137 and the rigid portion 440 may not be fixed to the X axis 110. The blade 105 may also rotate around the Z axis 220 and bend along the flexible portion 137 of the blade 105.

The direction of flow, the bending of the blade, and the rotation of the blade may be in other directions, axes, or combinations of axes other than what is shown in FIGS. 1-4. Furthermore, the construction of the blade may use other flexible and non-flexible materials than the materials disclosed herein.

Other embodiments may be within the scope of the following claims. 

1. A method for increasing efficiency of a symmetrical blade, the method comprising: providing a rigid portion of the symmetrical blade; and providing a flexible portion of the symmetrical blade, wherein the rigid portion of the symmetrical blade is connected to the flexible portion of the symmetrical blade, wherein the flexible portion of the symmetrical blade is adapted to bend with a flow across the symmetrical blade.
 2. The method of claim 1, wherein the symmetrical blade is adapted to rotate in one direction for a bi-directional flow across the symmetrical blade.
 3. The method of claim 2, wherein the symmetrical blade is adapted for at least one of a Wave Energy Conversion (WEC) system, a fan, an exhaust system, a blowing system, and a suction system.
 4. The method of claim 3, further comprising: fixing the rigid portion of the symmetrical blade to an axis perpendicular to a direction of flow.
 5. The method of claim 4, further comprising: rotating the symmetrical blade in a direction orthogonal to the direction of flow and orthogonal to the bending of the symmetrical blade.
 6. The method of claim 5, wherein the rigid portion comprises metal, wood, and plastic, wherein the flexible portion comprises plastic and rubber.
 7. The method of claim 6, wherein the symmetrical blade comprises a pear-shaped blade.
 8. The method of claim 6, wherein the symmetrical blade comprises a rectangular-shaped blade.
 9. A system for increasing the efficiency of a turbine with a symmetrical blade, the system comprising: a rigid portion of the symmetrical blade; and a flexible portion of the symmetrical blade, the flexible portion of the symmetrical blade connecting to the rigid portion of the symmetrical blade, wherein the flexible portion is adapted to bend in a direction of flow across the symmetrical blade.
 10. The system of claim 9, wherein a geometry of the symmetrical blade varies to reduce an amount of loss from an entirely rigid, symmetrical blade.
 11. The system of claim 9, wherein a geometry of the symmetrical blade varies to increase the efficiency of the symmetrical blade over an entirely rigid symmetrical blade.
 12. The system of claim 9, wherein the geometry of the symmetrical blade varies with the direction of flow.
 13. The system of claim 9, wherein the symmetrical blade is adapted to rotate in a single direction for a bi-directional flow across the symmetrical blade.
 14. The system of claim 13, wherein the symmetrical blade comprises plastic and metal.
 15. An apparatus comprising a flexible symmetric blade adapted to increase an efficiency of a Wave Energy Conversion (WEC) system, wherein the geometry of the symmetrical blade is adapted to vary to reduce the loss of the symmetrical blade over an entirely rigid symmetrical blade.
 16. The apparatus of claim 15, wherein the flexible symmetric blade remains unfixed to an axis perpendicular to a direction of flow, the flexible symmetric blade comprising an entirely flexible symmetric blade.
 17. The apparatus of claim 15, wherein the flexible symmetric blade is adapted to provide additional impulse to the apparatus.
 18. A turbine system, the turbine system comprising a rigid symmetrical blade adapted to rotate in a direction orthogonal to a direction of flow across the symmetrical blade.
 19. A turbine system, the turbine system comprising: a first rigid portion of a symmetrical blade; a second rigid portion of the symmetrical blade and a flexible portion of the symmetrical blade, the flexible portion of the symmetrical blade connected between the first and the second rigid portions of the symmetrical blade, wherein the flexible portion is adapted to bend in a direction of flow across the symmetrical blade.
 20. The turbine system of claim 19, wherein the symmetrical blade may rotate around an axis perpendicular to the direction of flow, wherein the symmetrical blade is adapted to rotate in a single direction regardless of the direction of flow. 